Background: Articulation is a process that allows air to pass through vocal cords and then form words and syllables using the tongue, teeth, mentum and palatine tonsils. A person who has pronunciation problems produces, syllables or words inaccurately so; the auditoria have got difficulty to understand what did say, such that the listener has difficulty in understanding what is being said. Due to being genetically different the Down syndrome individual has difficulty with speech due to structural defects in the mouth and problems with the mouth-tongue muscles. Aim: Here the determination of the articulation (pronunciation) problems and the probable causes of the determined problems have been studied. Methods: This study involved children without hearing loss problems; 17 females and 23 males who have Down syndrome and were ages between 3 and 12 years. The Ankara articulation test (AAT) was applied to the individuals. The articulation (pronunciation) ages have been determined according to the ATT. By the detailed assessment of the ATT, it was determined which voices were uttered correctly or not. Through a family interview survey, the information that affected the development of the Down syndrome child’s speech and academic development was obtained. Through a patient identification survey, the education and health information that may effect the speech development were obtained. Through an oral motor assessment survey, the information regarding the competence of oral motor skills that may effect articulation problems were collected. The data were analyzed. Using a family survey, child identification survey and an oral motor assessment survey the correlation between articulation age and articulation defects were viewed. Results: It has been detected that the articulation age of Down syndrome children between 3 and 12 years of age are quite a bit lower when compared to the chronological age according to the ATT. Moreover, in terms of results from the ATT, children with Down syndrome whose cronological age is 8 years 7 months have a 3 year 5 months’ articulation age according to the ATT. They have some difficulties with Turkish vowels such as (/a/, /e/, /ı/, /i/). Also they have some difficulties with consonants such as (/r/, /j/, /z/, /ş/, /z/, /l/, /s/, /n/). Articulation defects at various levels have been detected for all Down syndrome children. Articulation (pronunciation) problems were encountered less in children from highly educated and more concerned families. It has been shown that articulation (pronunciation) problems are less children who receive early treatment, therapy and education services. Conclusion: Significant correlation between the level of articulation usage by individuals and frequency of the articulation problem were detected. For this reason, attaching importance to oral motor studies are considered. Raising parental awareness is required on prenatal diagnosis of Down syndrome. By treating the problems of the speech organs at an early age and including the children who have Down syndrome into the early education programs around 0–3 years and accurate intervention during critical periods, the articulation problems can be reduced. Using a wider age range and having more participants, it is considered that more efficient results may be obtained.